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* manual: Add Descriptor-Relative Access sectionFlorian Weimer2024-08-273-10/+235
| | | | | | | | | | | Reference this new section from the O_PATH documentation. And document the functions openat, openat64, fstatat, fstatat64. (The safety assessment for fstatat was already obsolete because current glibc assumes kernel support for the underlying system call.) Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* ungetc: Fix uninitialized read when putting into unused streams [BZ #27821]Siddhesh Poyarekar2024-08-151-5/+3
| | | | | | | | | | | | | | | | | | | | When ungetc is called on an unused stream, the backup buffer is allocated without the main get area being present. This results in every subsequent ungetc (as the stream remains in the backup area) checking uninitialized memory in the backup buffer when trying to put a character back into the stream. Avoid comparing the input character with buffer contents when in backup to avoid this uninitialized read. The uninitialized read is harmless in this context since the location is promptly overwritten with the input character, thus fulfilling ungetc functionality. Also adjust wording in the manual to drop the paragraph that says glibc cannot do multiple ungetc back to back since with this change, ungetc can actually do this. Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* manual: Document dprintf and vdprintfFlorian Weimer2024-08-131-0/+27
| | | | Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* manual: Document generic printf error codesFlorian Weimer2024-08-131-0/+23
| | | | | | Describe EOVERFLOW, ENOMEN, EILSEQ. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* manual/stdio: Further clarify putc, putwc, getc, and getwcArjun Shankar2024-08-061-17/+10
| | | | | | | | | | | This is a follow-up to 10de4a47ef3f481592e3c62eb07bcda23e9fde4d that reworded the manual entries for putc and putwc and removed any performance claims. This commit further clarifies these entries and brings getc and getwc in line with the descriptions of putc and putwc, removing any performance claims from them as well. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* mremap: Update manual entryH.J. Lu2024-08-011-7/+35
| | | | | | | | | | Update mremap manual entry: 1. Change mremap to variadic. 2. Document MREMAP_FIXED and MREMAP_DONTUNMAP. Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* manual: make setrlimit() description less ambiguousLukas Bulwahn2024-07-291-2/+2
| | | | | | | | | | | The existing description for setrlimit() has some ambiguity. It could be understood to have the semantics of getrlimit(), i.e., the limits from the process are stored in the provided rlp pointer. Make the description more explicit that rlp are the input values, and that the limits of the process is changed with this function. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* manual/stdio: Clarify putc and putwcArjun Shankar2024-07-291-6/+6
| | | | | | | | | | | | | | The manual entry for `putc' described what "most systems" do instead of describing the glibc implementation and its guarantees. This commit fixes that by warning that putc may be implemented as a macro that double-evaluates `stream', and removing the performance claim. Even though the current `putc' implementation does not double-evaluate `stream', offering this obscure guarantee as an extension to what POSIX allows does not seem very useful. The entry for `putwc' is also edited to bring it in line with `putc'. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* manual: Do not mention STATIC_TLS in dynamic linker hardening recommendationsFlorian Weimer2024-07-241-12/+12
| | | | | | | The current toolchain does not consistently generate it, and glibc does not use it. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
* contrib.texi: Fix format of MIPS and RISC-VAndreas K. Hüttel2024-07-211-3/+3
| | | | Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
* install.texi: bump "latest verified" versionsAndreas K. Hüttel2024-07-211-9/+9
| | | | Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
* contrib.texi: updateAndreas K. Hüttel2024-07-201-5/+29
| | | | Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
* Linux: Make __rseq_size useful for feature detection (bug 31965)Florian Weimer2024-07-091-2/+6
| | | | | | | | | | | The __rseq_size value is now the active area of struct rseq (so 20 initially), not the full struct size including padding at the end (32 initially). Update misc/tst-rseq to print some additional diagnostics. Reviewed-by: Michael Jeanson <mjeanson@efficios.com> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
* manual: add syscallsDJ Delorie2024-07-096-37/+96
| | | | | | | | | | | | | | The purpose of this patch is to add some system calls that (1) aren't otherwise documented, and (2) are merely redirected to the kernel, so can refer to their documentation; and define a standard way of doing so in the future. A more detailed explaination of how system calls are wrapped is added along with reference to the Linux Man-Pages project. Default version of man-pages is in configure.ac but can be overridden by --with-man-pages=X.Y Reviewed-by: Alejandro Colomar <alx@kernel.org>
* manual: Recommendations for dynamic linker hardeningFlorian Weimer2024-07-031-0/+558
| | | | | | | | | This new section in the manual provides recommendations for use of glibc in environments with higher integrity requirements. It's reflecting both current implementation shortcomings, and challenges we inherit from ELF and psABI requirements. Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
* Add --disable-static-c++-tests option [BZ #31797]H.J. Lu2024-07-021-0/+8
| | | | | | | | | | | | By default, if the C++ toolchain lacks support for static linking, configure fails to find the C++ header files and the glibc build fails. The --disable-static-c++-link-check option allows the glibc build to finish, but static C++ tests will fail if the C++ toolchain doesn't have the necessary static C++ libraries which may not be easily installed. Add --disable-static-c++-tests option to skip the static C++ link check and tests. This fixes BZ #31797. Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
* Add --disable-static-c++-link-check option [BZ #31412]H.J. Lu2024-07-021-0/+8
| | | | | | | | | | | | The current minimum GCC version of glibc build is GCC 6.2 or newer. But building i686 glibc with GCC 6.4 on Fedora 40 failed since the C++ header files couldn't be found which was caused by the static C++ link check failure due to missing __divmoddi4 which was referenced in i686 libc.a and added to GCC 7. Add --disable-static-c++-link-check configure option to disable the static C++ link test. The newly built i686 libc.a can be used by GCC 6.4 to create static C++ tests. This fixes BZ #31412. Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
* Update mmap() flags and errors listsDJ Delorie2024-07-011-16/+126
| | | | | | | | | Extend the list of MAP_* macros to include all macros available to the average program (gcc -E -dM | grep MAP_*) Extend the list of errno codes. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* Fix strnlen doc re array sizePaul Eggert2024-06-261-7/+10
| | | | | | | | | * manual/string.texi: For strnlen (s, maxlen), do not say that s must be of size maxlen, as it can be smaller if it is null-terminated. This should help avoid confusion such as seen in <https://lists.gnu.org/r/bug-gnulib/2024-06/msg00280.html>. Mention that strnlen and wcsnlen have been in POSIX since POSIX.1-2008.
* INSTALL: Fix typo ibmlondouble to ibmlongdoubleJoe Simmons-Talbott2024-06-241-1/+1
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* elf: Remove LD_HWCAP_MASK / tunable glibc.cpu.hwcap_maskStefan Liebler2024-06-182-17/+6
| | | | | | | | | | | | Remove the environment variable LD_HWCAP_MASK and the tunable glibc.cpu.hwcap_mask as those are not used anymore in common-code after removal in elf/dl-cache.c:search_cache(). The only remaining user is sparc32 where it is used in elf_machine_matches_host(). If sparc32 does not need it anymore, we can get rid of it at all. Otherwise we could also move LD_HWCAP_MASK / tunable glibc.cpu.hwcap_mask to be sparc32 specific. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Convert to autoconf 2.72 (vanilla release, no distribution patches)Andreas K. Hüttel2024-06-171-1/+1
| | | | | | | As discussed at the patch review meeting Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org> Reviewed-by: Simon Chopin <simon.chopin@canonical.com>
* Implement C23 exp2m1, exp10m1Joseph Myers2024-06-171-0/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | C23 adds various <math.h> function families originally defined in TS 18661-4. Add the exp2m1 and exp10m1 functions (exp2(x)-1 and exp10(x)-1, like expm1). As with other such functions, these use type-generic templates that could be replaced with faster and more accurate type-specific implementations in future. Test inputs are copied from those for expm1, plus some additions close to the overflow threshold (copied from exp2 and exp10) and also some near the underflow threshold. exp2m1 has the unusual property of having an input (M_MAX_EXP) where whether the function overflows (under IEEE semantics) depends on the rounding mode. Although these could reasonably be XFAILed in the testsuite (as we do in some cases for arguments very close to a function's overflow threshold when an error of a few ulps in the implementation can result in the implementation not agreeing with an ideal one on whether overflow takes place - the testsuite isn't smart enough to handle this automatically), since these functions aren't required to be correctly rounding, I made the implementation check for and handle this case specially. The Makefile ordering expected by lint-makefiles for the new functions is a bit peculiar, but I implemented it in this patch so that the test passes; I don't know why log2 also needed moving in one Makefile variable setting when it didn't in my previous patches, but the failure showed a different place was expected for that function as well. The powerpc64le IFUNC setup seems not to be as self-contained as one might hope; it shouldn't be necessary to add IFUNCs for new functions such as these simply to get them building, but without setting up IFUNCs for the new functions, there were undefined references to __GI___expm1f128 (that IFUNC machinery results in no such function being defined, but doesn't stop include/math.h from doing the redirection resulting in the exp2m1f128 and exp10m1f128 implementations expecting to call it). Tested for x86_64 and x86, and with build-many-glibcs.py.
* Implement C23 log10p1Joseph Myers2024-06-171-0/+14
| | | | | | | | | | | | | | C23 adds various <math.h> function families originally defined in TS 18661-4. Add the log10p1 functions (log10(1+x): like log1p, but for base-10 logarithms). This is directly analogous to the log2p1 implementation (except that whereas log2p1 has a smaller underflow range than log1p, log10p1 has a larger underflow range). The test inputs are copied from those for log1p and log2p1, plus a few more inputs in that wider underflow range. Tested for x86_64 and x86, and with build-many-glibcs.py.
* Implement C23 logp1Joseph Myers2024-06-171-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | C23 adds various <math.h> function families originally defined in TS 18661-4. Add the logp1 functions (aliases for log1p functions - the name is intended to be more consistent with the new log2p1 and log10p1, where clearly it would have been very confusing to name those functions log21p and log101p). As aliases rather than new functions, the content of this patch is somewhat different from those actually adding new functions. Tests are shared with log1p, so this patch *does* mechanically update all affected libm-test-ulps files to expect the same errors for both functions. The vector versions of log1p on aarch64 and x86_64 are *not* updated to have logp1 aliases (and thus there are no corresponding header, tests, abilist or ulps changes for vector functions either). It would be reasonable for such vector aliases and corresponding changes to other files to be made separately. For now, the log1p tests instead avoid testing logp1 in the vector case (a Makefile change is needed to avoid problems with grep, used in generating the .c files for vector function tests, matching more than one ALL_RM_TEST line in a file testing multiple functions with the same inputs, when it assumes that the .inc file only has a single such line). Tested for x86_64 and x86, and with build-many-glibcs.py.
* Minor code improvement to timespec_subtract examplePaul Eggert2024-06-151-3/+3
| | | | | | | This saves a few instructions. BORROW cannot be -1, since NSEC_DIFF is at most 999999999. Idea taken from Gnulib, here: https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=fe33f943054b93af8b965ce6564b8713b0979a21
* Modernize and fix doc’s “Date and Time” (BZ 31876)Paul Eggert2024-06-158-462/+584
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | POSIX.1-2024 (now official) specifies tm_gmtoff and tm_zone. This is a good time to update the manual’s “Date and Time” chapter so I went through it, fixed some outdated stuff that had been in there for decades, and improved it to match POSIX.1-2024 better and to clarify some implementation-defined behavior. Glibc already conforms to POSIX.1-2024 in these matters, so this is merely a documentation change. * manual/examples/strftim.c: Use snprintf instead of now-deprecated function asctime. Check for localtime failure. Simplify by using puts instead of fputs. Prefer ‘buf, sizeof buf’ to less-obvious ‘buffer, SIZE’. * manual/examples/timespec_subtract.c: Modernize to use struct timespec not struct timeval, and rename from timeval_subtract.c. All uses changed. Check for overflow. Do not check for negative return value, which ought to be OK since negative time_t is OK. Use GNU indenting style. * manual/time.texi: Document CLOCKS_PER_SEC, TIME_UTC, timespec_get, timespec_getres, strftime_l. Document the storage lifetime of tm_zone and of tzname. Caution against use of tzname, timezone and daylight, saying that these variables have unspecified values when TZ is geographic. This is what glibc actually does (contrary to what the manual said before this patch), and POSIX is planned to say the same thing <https://austingroupbugs.net/view.php?id=1816>. Also say that directly accessing the variables is not thread-safe. Say that localtime_r and ctime_r don’t necessarily set time zone state. Similarly, in the tzset documentation, say that it is called by ctime, localtime, mktime, strftime, not that it is called by all time conversion functions that depend on the time zone. Say that tm_isdst is useful mostly just for mktime, and that other uses should prefer tm_gmtoff and tm_zone instead. Do not say that strftime ignores tm_gmtoff and tm_zone, because it doesn’t do that. Document what gmtime does to tm_gmtoff and tm_zone. Say that the asctime, asctime_r, ctime, and ctime_r are now deprecated and/or obsolescent, and that behavior is undefined if the year is < 1000 or > 9999. Document strftime before these now-obsolescent functions, so that readers see the useful function first. Coin the terms “geographical format” and “proleptic format” for the two main formats of TZ settings, to simplify exposition. Use this wording consistently. Update top-level proleptic syntax to match POSIX.1-2024, which glibc already implements. Document the angle-bracket quoted forms of time zone abbreviations in proleptic TZ. Say that time zone abbreviations can contain only ASCII alphanumerics, ‘+’, and ‘-’. Document what happens if the proleptic form specifies a DST abbreviation and offset but omits the rules. POSIX says this is implementation-defined so we need to document it. Although this documentation mentions ‘posixrules’ tersely, we need to rethink ‘posixrules’ since I think it stops working after 2038. Clarify wording about TZ settings beginning with ‘;’. Say that timegm is in ISO C (as of C23). Say that POSIX.1-2024 removed gettimeofday. Say that tm_gmtoff and tm_zone are extensions to ISO C, which is clearer than saying they are invisible in a struct ISO C enviroment, and gives us more wiggle room if we want to make them visible in strict ISO C, something that ISO C allows. Drop mention of old standards like POSIX.1c and POSIX.2-1992 in the text when the history is so old that it’s no longer useful in a general-purpose manual. Define Coordinated Universal Time (UTC), time zone, time zone ruleset, and POSIX Epoch, and use these phrases more consistently. Improve TZ examples to show more variety, and to reflect current practice and timestamps. Remove obsolete example about Argentina. Add an example for Ireland. Don’t rely on GCC extensions when explaining ctime_r. Do not say that difftime produces the mathematically correct result, since it might be inexact. For clock_t don’t say “as in the example above” when there is no such example, and don’t say that casting to double works “properly and consistently no matter what”, as it suffers from rounding and overflow. Don’t say broken-down time is not useful for calculations; it’s merely painful. Say that UTC is not defined before 1960. Rename Time Zone Functions to Time Zone State. All uses changed. Update Internet RFC 822 → 5322, 1305 → 5905. Drop specific years of ISO 8601 as they don’t matter. Minor style changes: @code{"..."} → @t{"..."} to avoid overquoting in info files, @code → @env for environment variables, Daylight Saving Time → daylight saving time, white space → whitespace, prime meridian → Prime Meridian.
* manual: minor language fix (bz 31340)Andreas K. Hüttel2024-06-151-1/+1
| | | | | Resolves: https://sourceware.org/bugzilla/show_bug.cgi?id=31340 Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
* Improve doc for time_t range (BZ 31808)Paul Eggert2024-06-041-1/+11
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* x86: Add seperate non-temporal tunable for memsetNoah Goldstein2024-05-301-1/+15
| | | | | | | | | | | The tuning for non-temporal stores for memset vs memcpy is not always the same. This includes both the exact value and whether non-temporal stores are profitable at all for a given arch. This patch add `x86_memset_non_temporal_threshold`. Currently we disable non-temporal stores for non Intel vendors as the only benchmarks showing its benefit have been on Intel hardware. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* manual: clarify defintions of floating point exponent bounds (bug 31518)Andreas Schwab2024-05-211-5/+5
| | | | | For decimal exponent bounds the range is inclusive, for binary exponent bounds the range is exclusive.
* Implement C23 log2p1Joseph Myers2024-05-201-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | C23 adds various <math.h> function families originally defined in TS 18661-4. Add the log2p1 functions (log2(1+x): like log1p, but for base-2 logarithms). This illustrates the intended structure of implementations of all these function families: define them initially with a type-generic template implementation. If someone wishes to add type-specific implementations, it is likely such implementations can be both faster and more accurate than the type-generic one and can then override it for types for which they are implemented (adding benchmarks would be desirable in such cases to demonstrate that a new implementation is indeed faster). The test inputs are copied from those for log1p. Note that these changes make gen-auto-libm-tests depend on MPFR 4.2 (or later). The bulk of the changes are fairly generic for any such new function. (sysdeps/powerpc/nofpu/Makefile only needs changing for those type-generic templates that use fabs.) Tested for x86_64 and x86, and with build-many-glibcs.py.
* manual: add dup3DJ Delorie2024-05-131-0/+8
| | | | Reviewed-by: Florian Weimer <fweimer@redhat.com>
* LoongArch: Add glibc.cpu.hwcap support.caiyinyu2024-04-241-1/+4
| | | | | | | | | | | | | | | | The current IFUNC selection is always using the most recent features which are available via AT_HWCAP. But in some scenarios it is useful to adjust this selection. The environment variable: GLIBC_TUNABLES=glibc.cpu.hwcaps=-xxx,yyy,zzz,.... can be used to enable HWCAP feature yyy, disable HWCAP feature xxx, where the feature name is case-sensitive and has to match the ones used in sysdeps/loongarch/cpu-tunables.c. Signed-off-by: caiyinyu <caiyinyu@loongson.cn>
* aarch64: Enhanced CPU diagnostics for ld.soFlorian Weimer2024-04-081-0/+34
| | | | | | | This prints some information from struct cpu_features, and the midr_el1 and dczid_el0 system register contents on every CPU. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
* x86: Add generic CPUID data dumper to ld.so --list-diagnosticsFlorian Weimer2024-04-081-1/+84
| | | | | | | | | | | This is surprisingly difficult to implement if the goal is to produce reasonably sized output. With the current approaches to output compression (suppressing zeros and repeated results between CPUs, folding ranges of identical subleaves, dealing with the %ecx reflection issue), the output is less than 600 KiB even for systems with 256 logical CPUs. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* Fix bsearch, qsort doc to match POSIX betterPaul Eggert2024-04-061-24/+36
| | | | | | | | | | | | | | | | | | | | | | * manual/search.texi (Array Search Function): Correct the statement about lfind’s mean runtime: it is proportional to a number (not that number), and this is true only if random elements are searched for. Relax the constraint on bsearch’s array argument: POSIX says it need not be sorted, only partially sorted. Say that the first arg passed to bsearch’s comparison function is the key, and the second arg is an array element, as POSIX requires. For bsearch and qsort, say that the comparison function should not alter the array, as POSIX requires. For qsort, say that the comparison function must define a total order, as POSIX requires, that it should not depend on element addresses, that the original array index can be used for stable sorts, and that if qsort still works if memory allocation fails. Be more consistent in calling the array elements “elements” rather than “objects”. Co-authored-by: Zack Weinberg <zack@owlfolio.org>
* misc: Add support for Linux uio.h RWF_NOAPPEND flagStafford Horne2024-04-041-0/+4
| | | | | | | | | | | | | | | | | | | In Linux 6.9 a new flag is added to allow for Per-io operations to disable append mode even if a file was opened with the flag O_APPEND. This is done with the new RWF_NOAPPEND flag. This caused two test failures as these tests expected the flag 0x00000020 to be unused. Adding the flag definition now fixes these tests on Linux 6.9 (v6.9-rc1). FAIL: misc/tst-preadvwritev2 FAIL: misc/tst-preadvwritev64v2 This patch adds the flag, adjusts the test and adds details to documentation. Link: https://lore.kernel.org/all/20200831153207.GO3265@brightrain.aerifal.cx/ Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* manual: significand() uses FLT_RADIX, not 2Alejandro Colomar2024-04-031-1/+1
| | | | | | | | | | | | | | It's implemented using scalb(), which uses FLT_RADIX, AFAIK. Link: <https://lore.kernel.org/linux-man/ZeYKUOKYS7G90SaV@debian/T/#mf21ab57e16b92eb6be6c7df79dc0eb43d4454056> Reported-by: Morten Welinder <mwelinder@gmail.com> Cc: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org> Cc: Vincent Lefevre <vincent@vinc17.net> Cc: DJ Delorie <dj@redhat.com> Cc: Paul Zimmermann <Paul.Zimmermann@inria.fr> Cc: Andreas Schwab <schwab@linux-m68k.org> Signed-off-by: Alejandro Colomar <alx@kernel.org> Reviewed-by: DJ Delorie <dj@redhat.com>
* manual: Clarify return value of cbrt(3)Alejandro Colomar2024-04-031-2/+6
| | | | | | | | | | | | | Link: <https://lore.kernel.org/linux-man/ZeYKUOKYS7G90SaV@debian/T/#mff0ab388000c6afdb5e5162804d4a0073de481de> Reported-by: Morten Welinder <mwelinder@gmail.com> Cowritten-by: Morten Welinder <mwelinder@gmail.com> Cc: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org> Cc: Vincent Lefevre <vincent@vinc17.net> Cc: DJ Delorie <dj@redhat.com> Cc: Paul Zimmermann <Paul.Zimmermann@inria.fr> Cc: Andreas Schwab <schwab@linux-m68k.org> Signed-off-by: Alejandro Colomar <alx@kernel.org> Reviewed-by: DJ Delorie <dj@redhat.com>
* manual: floor(log2(fabs(x))) has rounding errorsAlejandro Colomar2024-04-031-2/+5
| | | | | | | | | | | | Link: <https://inbox.sourceware.org/libc-alpha/20240305150131.GD3653@qaa.vinc17.org/T/#m3ceecda630012995339bcc5448fee451cf277a8b> Reported-by: Vincent Lefevre <vincent@vinc17.net> Suggested-by: Vincent Lefevre <vincent@vinc17.net> Reviewed-by: DJ Delorie <dj@redhat.com> Cc: Morten Welinder <mwelinder@gmail.com> Cc: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org> Cc: Paul Zimmermann <Paul.Zimmermann@inria.fr> Cc: Andreas Schwab <schwab@linux-m68k.org> Signed-off-by: Alejandro Colomar <alx@kernel.org>
* manual: logb(x) is floor(log2(fabs(x)))Alejandro Colomar2024-04-031-1/+1
| | | | | | | | | | | | | | log2(3) doesn't accept negative input, but it seems logb(3) does accept it. Link: <https://lore.kernel.org/linux-man/ZeYKUOKYS7G90SaV@debian/T/#u> Reported-by: Morten Welinder <mwelinder@gmail.com> Reviewed-by: DJ Delorie <dj@redhat.com> Cc: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org> Cc: Vincent Lefevre <vincent@vinc17.net> Cc: Paul Zimmermann <Paul.Zimmermann@inria.fr> Cc: Andreas Schwab <schwab@linux-m68k.org> Signed-off-by: Alejandro Colomar <alx@kernel.org>
* Always define __USE_TIME_BITS64 when 64 bit time_t is usedAdhemerval Zanella2024-04-022-0/+10
| | | | | | | | | | | | | | | | | | | | It was raised on libc-help [1] that some Linux kernel interfaces expect the libc to define __USE_TIME_BITS64 to indicate the time_t size for the kABI. Different than defined by the initial y2038 design document [2], the __USE_TIME_BITS64 is only defined for ABIs that support more than one time_t size (by defining the _TIME_BITS for each module). The 64 bit time_t redirects are now enabled using a different internal define (__USE_TIME64_REDIRECTS). There is no expected change in semantic or code generation. Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, and arm-linux-gnueabi [1] https://sourceware.org/pipermail/libc-help/2024-January/006557.html [2] https://sourceware.org/glibc/wiki/Y2038ProofnessDesign Reviewed-by: DJ Delorie <dj@redhat.com>
* manual/tunables - Add entry for enable_secure tunable.Joe Talbott2024-03-011-0/+10
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* trivial doc fix: remove weird phrase "syscall takes zero to five arguments"Askar Safin2024-02-141-2/+1
| | | | | | | | | | | | | "number of arguments, from zero to five" is wrong, because on Linux maximal number of arguments is 6, not 5. Also, maximal number of arguments is kernel-dependent, so let's not include it here at all. Moreover, "Each kind of system call has a definite number of arguments" is questionable. Think about SYS_open on Linux, which takes 2 or 3 arguments. Or SYS_clone on Linux x86_64, which takes 2 to 5 arguments. So I propose to fully remove this sentence. Signed-off-by: Askar Safin <safinaskar@zohomail.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* stdlib: fix qsort example in manualPaul Eggert2024-02-011-9/+12
| | | | | | | | * manual/search.texi (Comparison Functions, Array Sort Function): Sort an array of long ints, not doubles, to avoid hassles with NaNs. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
* manual: Fix up stdbit.texiJakub Jelinek2024-02-011-1/+1
| | | | | | My recent change broke make pdf and in other documentation formats results in weird rendering and invalid URL, all because of a forgotten comma to separate @uref arguments.
* Refer to C23 in place of C2X in glibcJoseph Myers2024-02-015-42/+42
| | | | | | | | | | | | | | | WG14 decided to use the name C23 as the informal name of the next revision of the C standard (notwithstanding the publication date in 2024). Update references to C2X in glibc to use the C23 name. This is intended to update everything *except* where it involves renaming files (the changes involving renaming tests are intended to be done separately). In the case of the _ISOC2X_SOURCE feature test macro - the only user-visible interface involved - support for that macro is kept for backwards compatibility, while adding _ISOC23_SOURCE. Tested for x86_64.
* Use gcc __builtin_stdc_* builtins in stdbit.h if possibleJakub Jelinek2024-01-311-1/+7
| | | | | | | | | | | | | | | | | The following patch uses the GCC 14 __builtin_stdc_* builtins in stdbit.h for the type-generic macros, so that when compiled with GCC 14 or later, it supports not just 8/16/32/64-bit unsigned integers, but also 128-bit (if target supports them) and unsigned _BitInt (any supported precision). And so that the macros don't expand arguments multiple times and can be evaluated in constant expressions. The new testcase is gcc's gcc/testsuite/gcc.dg/builtin-stdc-bit-1.c adjusted to test stdbit.h and the type-generic macros in there instead of the builtins and adjusted to use glibc test framework rather than gcc style tests with __builtin_abort (). Signed-off-by: Jakub Jelinek <jakub@redhat.com> Reviewed-by: Joseph Myers <josmyers@redhat.com>
* INSTALL, install.texi: minor updates, regenerateAndreas K. Hüttel2024-01-311-3/+3
| | | | Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>